1. Technical Field of the Invention
The present invention generally relates to a connecting structure for battery terminals and, more particularly, to a connecting structure for surely connecting battery terminals to battery electrodes of corresponding polarity of a battery body mounted on a vehicle without miscontact of the battery terminals with the battery electrode.
2. Related Art
FIGS. 5 and 6 illustrate a related connecting structure for fastening and fixing battery terminals, provided at an end of an electric wire connected to various kinds of electrical equipment, to battery electrodes of a battery body, mounted on a vehicle, by screw members.
This connecting structure for a battery terminal is disclosed in JP-A-4-220947, and configured so that a positive battery electrode 3 and a negative battery electrode 4 of the vehicle-mounted battery body 1 are quadrangular-prism-like posts 3b and 4b respectively erected on base potions 3a and 4a on the top surface of the battery body 1.
Each of the posts 3b and 4b has a flat abutting surface 6 or 7 formed at the tip thereof. In each of abutting surface portions 6 and 7, a screw hole 8 or 9 for securing a battery terminal 11 or 12 (to be described later) by screws is formed. These screw holes 8 and 9 are provided so that the central axes thereof are eccentric from the central portions of the abutting surfaces in different directions in such a way as to make the position of the central axis of the positive electrode with respect to the center of the corresponding screw hole differ from that of the central axis of the negative electrode with respect to the center of the other screw hole.
Each of the battery terminals 11 and 12 includes: a flat plate portion 11a or 12a adapted to abut against a corresponding one of abutting surfaces 6 or 7 respectively formed at the tips of the posts 3b and 4b; an abutting wall portion 11b or 12b which is erected on an edge portion of a corresponding one of these flat plate portions 11a and 12a and abuts against an adjacent side surface of the corresponding post 3b or 4b; and a wire cramping portion 11a or 12c to which a corresponding electric wire 16 or 17 is press-attached.
Further, in each of the flat plate portions 11a and 12a, a screw insertion hole 14 or 15 is provided at an eccentric position corresponding to a corresponding one of the screw holes 8 and 9 respectively formed in the posts 3b and 4b to be connected thereto.
In the aforementioned connecting structure for the battery terminals, the flat plate portions 11a and 12a of the battery terminals 11 and 12 are set on the abutting surfaces 6 and 7 of the posts 3b and 4b so that the screw insertion holes 14 and 15 are aligned with the screw holes 8 and 9 of the posts 3b and 4b. Thus, each of the abutting wall portions 11b and 12b is caught on the corner portion of a corresponding one of the posts 3b and 4b. Consequently, the flat plate portions 11a and 12a serve as rotation inhibiting means.
Therefore, when fastened by bolts 19 screwed into the screw holes 8 and 9, the battery terminals 11 and 12 are restrained from rotating with respect to the posts 3b and 4b. This prevents a direction, in which the wire is drawn, from being changed.
Furthermore, as mentioned previously, the position, at which the screw hole 14 is formed, in the battery terminal 11 corresponding to one of the positive and negative battery electrodes is made to differ from the position, at which the screw hole 15 is formed, in the battery terminal 12 corresponding to the other battery electrode. This prevents each of the battery terminals from being misconnected to the battery electrode of the opposite polarity.
However, although the aforementioned related connecting structure for the battery terminals can prevent each of the battery terminals from being misconnected to the battery electrode of the different polarity, each of the battery electrodes 3 and 4 are exposed to the outside, so that the miscontact of each of the battery terminals 11 and 12 with the battery electrode of the opposite polarity may occur. Thus, there is a fear that electric backflow caused by the miscontact may break the equipment.
Especially, in recent years, there has been a tendency to enhance the efficiency of a vehicle power supply by increasing the voltage thereof. Thus, it is studied to replace 12-volt batteries and 24-volt batteries, which are currently in wide use, with 36-volt batteries. However, the implementation of a high-voltage battery increases the degree of seriousness of the problems of accidents due to the miscontact and sparks due to an arc.
Furthermore, recent increase in the power consumption of per vehicle results in increase in the number of batteries mounted on a vehicle. Thus, there is the need for contrivances to prevent occurrences of a misconnection and a miscontact of battery terminals with a plurality of batteries.
Accordingly, an object of the invention is to solve the problems, and to provide a connecting structure for reliably connecting each of battery terminals with a corresponding one of battery electrodes of a vehicle body without causing the miscontact of the battery terminals with the battery electrodes.
To achieve the foregoing object of the invention, according to the invention, there is provided a connecting structure for battery terminals, which is adapted to fasten and fix each of positive and negative battery terminals, which are respectively connected to end portions of wires, to one of battery electrodes, which is of corresponding polarity, of a battery body by screw members. In this structure, the battery body has positive and negative battery electrodes, which are provided in a plurality of accommodation spaces surrounded by an outer wall thereof, and also has terminal insertion openings each having a predetermined shape permitting only the battery terminals, which correspond to the battery electrodes in the accommodation spaces, to be fitted thereinto. Further, each of the battery terminals has a connecting flat plate portion having a transversal section of a predetermined shape, which is enabled to be fitted into a corresponding one of the terminal insertion openings. Furthermore, one of the terminal insertion openings has an opening width, which is wider than an opening width of the other terminal insertion opening, and also has an opening height that is higher than an opening height of the other terminal insertion opening.
With the aforementioned configuration, the electrical connection between the positive and negative battery terminals, which are connected to end portions of wires, and the battery electrodes is established by fastening and fixing each of the connecting flat plate portions, which is fitted into a corresponding one of the accommodation spaces from a corresponding one of the terminal insertion openings provided in the outer wall of the battery body, to the battery electrode of corresponding polarity by screw members.
Even when the battery terminal is misfitted into the terminal insertion opening corresponding to polarity, which does not correspond to this battery terminal, at that time, this battery terminal interferes with the opening edge of the terminal insertion opening because of the difference between the shape of the transversal section of the connecting flat plate portion and that of the terminal insertion opening. Consequently, this battery terminal cannot be fitted into this terminal insertion opening. Moreover, even the contact between this battery terminal and the battery electrode provided in the accommodation space, which is surrounded by the insulating wall portion, cannot be achieved.
Therefore, the misconnection is known without the contact between the battery terminal and the battery electrode, which do not correspond to each other, and the connection therebetween.
Further, because the battery electrodes are provided in the accommodation spaces surrounded by the insulating wall portions of the outer wall, arc caused at a moment, at which the battery terminal is in contact with the battery electrode, occurs in the accommodation space. Thus, sparks due to the arc do not go out of the battery body.
Further, preferably, a temporary latch mechanism for temporarily latching each of the battery terminals at a fastening/fixing position in a corresponding one of the accommodation spaces is provided between a corresponding one of the battery terminals to be fitted thereinto and an inner wall of each of the accommodation spaces.
Thus, when the battery terminal is fastened and fixed to the battery electrode of the battery body, the battery terminal is temporarily latched at the battery electrode by inserting this battery terminal into the accommodation space corresponding to an appropriate one of the battery electrodes to be connected thereto.
This prevents one hand of a worker from being used for supporting the battery terminal during an operation of fastening the battery terminal by the screw members, one hand of a worker is used for supporting the battery terminal. Consequently, the worker can easily perform the screwing operation by freely using both hands.
Furthermore, preferably, a circumferential portion of each of the terminal insertion openings is formed from an insulating member, whose abrasion resistance is higher than abrasion resistance of an insulating material of the outer wall.
This prevents the circumferential portion, which is rubbed when the battery terminal is inserted into or detached from the accommodation space, of each of the terminal insertion openings from wearing down and eroding during the attachment/detachment of the battery terminal. Additionally, this prevents the terminal insertion openings from being deformed.